Agri-News, September 26, 2006, Vol. 6, no. 19

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Physical quality of a yellow latossol under integrated crop-livestock system

Soil physical quality is essential to global sustainability of agroecosystems, once it is related to processes that are essential to agricultural crop development. This study aimed to evaluate physical attributes of a Yellow Latossol under different management systems in the savanna area in the state of Piaui. This study was developed in Uruçuí southwest of the state of Piauí. Three systems of soil management were studied: an area under conventional tillage (CT) with disk plowi and heavy harrow and soybean crop; an area under no-tillage with soybean-maize rotation and millet as cover crop (NT + M); two areas under Integrated Crop-Livestock System, with five-month pasture grazing and soybean cultivation and then continuous pasture grazing (ICL + S and ICL + P, respectively). Also, an area under Native Forest (NF) was studied. The soil depths studied were 0.00-0.05, 0.05-0.10 and 0.10-0.20 m. Soil bulk density, as well as porosity and stability of soil aggregates were analyzed as physical attributes. Anthropic action has changed the soil physical attributes, in depth, in most systems studied, in comparison to NF. In the 0.00 to 0.05 m depth, ICL + P showed higher soil bulk density value. As to macroporosity, there was no difference between the management systems studied and NF. The management systems studied changed the soil structure, having, as a result, a small proportion of soil in great aggregate classes (MWD). Converting native forest into agricultural production systems changes the soil physical quality. The Integrated Crop-Livestock System did not promote the improvement in soil physical quality.

Agri-News, October 3, 2006, Vol. 6, no. 20

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Agri-News, October 13, 2006, Vol. 6, no. 21

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Agri-News, October 24, 2006, Vol. 6, no. 22

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Agri-News, November 14, 2006, Vol. 6, no. 23

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Agri-News, November 22, 2006, Vol. 6, no. 24

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Agri-News, December 12, 2006, Vol. 6, no. 25

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Agri-News, January 5, 2007, Vol. 7, no. 1

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Agri-News, February 6, 2007, Vol. 7, no. 2

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Agri-News, March 6, 2007, Vol. 7, no. 3

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Agri-News, March 9, 2007, Vol. 7, no. 4

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Agri-News, April 5, 2007, Vol. 7, no. 5

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Agri-News, April 10, 2007, Vol. 7, no. 6

Crop and livestock summaries for the state of Iowa, produced by the Iowa Department of Agriculture.

Labile and stable fractions of soil organic matter under management systems and native cerrado

Soil organic matter can be analyzed on the basis of the different fractions. Changes in the levels of organic matter, caused by land use, can be better understood by alterations in the different compartments. The aim of this study was to evaluate the effect of different management systems on the labile and stable organic matter of a dystrophic Red Latosol (Oxisol). The following properties were determined: total organic C and total N (TOC and TN), particulate organic C and particulate N (POC and PN), organic C and N mineral-associated (MOC and NM) and particulate organic C associated with aggregate classes (POCA). Eight treatments were used: seven with soil management systems and one with native Cerrado as a reference. The experiment was designed to study the dynamics of systems of tillage and crop rotation, alternating in time and space. The experimental design was a randomized block design with three replications. The soil samples were collected from five depths: 0-5, 5-10, 10-20, 20-30 and 30-40 cm. Changes in organic C by land use occurred mainly in the fraction of particulate organic matter (> 53 mm). Proper management of grazing promoted increased levels of particulate organic matter by association with larger aggregates (2-8 mm), demonstrating the importance of the formation of this aggregate class for C protection in pasture.